It has been estimated that around 26 million people in US suffer from diabetes in 2010 and the number will significantly increase by 2030. People suffering from diabetes have certain other complications related to heart disease and stroke, hypertension, blindness and other eye problems, kidney disease, nervous system disorder and lower-limb amputations. People 40 years or older with diabetes have reported impaired sensation in their feet and majority of them end up with amputation (1). Thus, diabetic foot ulcer is one of the common complications found among people suffering from diabetes. It occurs as a result of various factors, such as mechanical changes in confirmation of the bony architecture of the foot, peripheral neuropathy and atherosclerotic peripheral arterial disease which are common conditions in diabetic population. (2).
The problem is so severe that a number of special clinics have open up which particularly take care of foot ulcers in patients with diabetes. The clinic's decision of preserving the tissue and continuing medical management without surgical detriment is a critical one. This decision which predicts the clinic outcome of these patients depends on the physical clinical exam as well as the degree of the vascularity and the level of the oxygenation of the tissue within the ulcers and its surroundings.
Diabetic patients need at least yearly diagnosis of their feet even if they have no initial signs of foot ulcers. If they develop some signs they are first examined through general clinical examination followed by other techniques present such as-ankle brachial index (ABI), transcutaneous oxygen measurements (TCPO2), pulse volume recordings and laser droppler flowmetry among others. In recent years imaging spectroscopy known as hyperspectral imaging (HIS) have emerged in different fields including medicine and is thus called medical hyperspectral imaging (MHSI). MHSI shows image of the area/biological tissue under investigation by calculating the oxygen delivery and oxygen extraction of each pixel in the image collected. Thus, it has some important clinical advantages by detecting the levels of oxygenation with the effected tissue and its surroundings. However, with the current visualization methods the images produced do not give a clear, easy to analyze and informative image for the evaluation of the level of oxygenation and de-oxygenation to predict the severity of the disease.
The MHSI technology is used with full 2D image hyperspectral cameras to provide saturation maps of a large surface or with line or point probes to provide localized information of the biological tissue under investigation. The MHSI technology enables to determine blood oxygen saturation and carbon monoxide saturation from the reflected spectrum of the tissue. A spectrum is build up by measuring the intensity of light reflected from the biological tissue at many different visible wavelengths and thus show the response of biological tissue as a function of wavelength. However, the image spectrum obtained is difficult to analyze, require highly trained staff, high-tech computers and monitors and thus is sometimes poor in predicting the severity of the medical condition or the extent of damage in a particular medical condition.
Thus, high quality imaging and its visualization to determine oxygen saturation levels and mapping is one of the key steps for useful early and non-invasive diagnosis of medical conditions and more specifically early or routine diagnosis of diabetic foot ulcers.